Tab interlock



y 1969 e. ALEXANDER TAB INTERLOCK Sheet Filed March 14, 1967 27 4 z 4 x 62 64 {Z United States Patent U.S. Cl. 74-483 Claims ABSTRACT OF THE DISCLOSURE A simple interlock mechanism and apparatus is disclosed herein, in which a plurality of actuable members are controlled so that upon actuation of any one of the actuable members from an unactuated to an actuated position, a previously actuated one of the actuable members is automatically caused to return to its unactuated position. The interlock apparatus is described herein in conjunction with an electric organ multielement tab switch. However, the interlock apparatus of the invention is not limited to such a switch, nor is it limited to electric switches in general, as will become apparent from the ensuing description.

Background of the invention Interlock mechanisms and apparatus are at present widely used, especially in conjunction with electric switching arrangements. For example, one widespread use of interlock apparatus is in conjunction with radio pushbutton tuners. In such tuners, for example, whenever a particular pushbutton is actuated, the previously actuated pushbutton is automatically returned to its unactuated position. Such prior art interlock apparatus and mechanisms, for the most part, however, are expensive and complicated.

Summary of the invention The present invention provides a simple interlock apparatus, which includes an elongated pliant member to which the selectively actuable members are linked. The pliant member is fastened at each end, and it extends transversely to the paths of the actuable members over spaced rollers. The action is such that whenever a particular actuable member is moved from its unactuated position to its actuated position, it pulls an intermediate portion of the pliant member in a transverse direction which, in turn, causes the pliant member to pull a previously actuated actuable member back to its unactuated position.

Brief description of drawings FIGURE 1 is a plan view of a multielement organ tab switch assembly in which the interlock apparatus of the invention is incorporated;

FIGURE 2 is a front elevation of the assembly of FIG- URE 1, with various elements removed, so as to reveal other, normally hidden, components in the assembly;

FIGURE 3 is a section of the assembly of FIGURE 1, taken substantially along the lines 3-3 of FIGURE 1;

FIGURE 4 is a bottom view of the assembly of FIG- URE 1;

FIGURE 5 is a fragmentary perspective view of the particular pliant member used in the illustrated embodiment; and

FIGURE 6 is a fragmentary exploded view, showing in perspective various components of a toggle control member used in the assembly.

Description of one embodiment of the invention The particular embodiment of the invention illustrated in the drawings, as mentioned above, is a multielement organ ta-b switch. This particular assembly includes, for example, a plurality of manually operable tabs 10, 12, 14, 16, 18 and 20, which are pivotally mounted on a support bracket, or base, 22. The individual tabs are mechanically coupled to corresponding electric switches, as will be described, and the tabs are interlocked by the mechanism and apparatus of the invention. The assembly is such that whenever the forward end, for example, of a particular tab is manually depressed, its corresponding switch is actuated. At the same time, a previously depressed tab, and its corresponding switch, are returned to their unactuated positions. The tabs are suitably inscribed, as shown in FIGURE 1, with the functions corresponding thereto.

A fixed contact board 24 is mounted on the underside of the bracket 22, as best shown in FIGURES 3 and 4. The contact board 24 may be composed, for example, of any suitable insulating material. A series of strips 26 are slidably mounted in the contact board 24, these latter strips being disposed parallel to one another, and spaced from one another, as best shown in FIGURE 4. The strips 26 are also composed of a suitable insulating material. These strips, as will be described, are individually controllable by the aforesaid tabs 10, 12, 14, 16, 18 and 20. That is, when any particular tab is depressed, its corresponding strip 26 is moved from its unactuated position to its actuated position in the contact board 24, and vice versa.

A plurality of electrical switch contacts 28 are mounted on the contact board 24 adjacent corresponding ones of the strips 26. These first groups of switch contacts represent the fixed contacts of the assembly. Further switch contacts 30 are carried by the various strips 26, and these latter contacts constitute the movable contacts of the assembly. When the various strips are moved from their unactuated to their actuated positions, the movable switch contacts 30 make corresponding selective electrical engagement with the associated fixed contacts 28.

The tabs 10, 12, 14, 16, 18 and 20 are mounted for individual pivotal movement about the axis of a shaft 32. The shaft 32 is mounted at one end in an upright bracket 34, the bracket being integral with the aforesaid bracket 22. The other end of the shaft 32 is mounted on an upright portion of a bracket 36. The latter bracket is also integral with the bracket 22. A further bracket 38 extends down from the underside of the bracket 22 and forms a support for a series of toggle mechanisms which are respectively associated with the tabs 10, 12, 14, 16, 18 and 20.

Each of the toggle mechanisms includes, for example, a flat member 40 composed of insulating material. Each member 40 has an elongated lower portion 40a extending into a cor-responding aperture in the bracket 38. The members 40 are each equipped with an integral stud 40b at the upper extremity, and these studs extend through apertures in corresponding ones of the switch strips 26. Each of the tabs 10, 12, 14, '16, 1 8 20 has integral sides 41a, 41b. These sides are mutually spaced and parallel, and they extend as a yoke down through the base 22. The members 40 are pivoted to the sides 41a and 41b of the tabs '10, 12, 14, 16, 18 and 20, as shown in FIGURES 2 and 3. A plurality of springs 42 are mounted on the lower portions 40a of the members 40, and these springs bias the members 40 in an upper direction.

-It will be appreciated that the assemblies described in the preceding paragraph constitute, in each instance, an overcenter type of toggle mechanism. That is, when the forward end of the tab 10, for example, is pushed down to its actuated position, the corresponding member 40 is pivoted back across the vertical dead-center plane, and the corresponding spring 42 biases the member 40 upwardly towards the base 22, so as to hold the tab 10 in the down position. Likewise, when the tab 10 is returned to its unactauated position, by pushing down the forward end of another tab, the corresponding member 40 associated with the tab '10 is pivoted forward through the dead-center plane, and again the corresponding spring 42 biases the member 40 upwardly, so as to hold the tab in its unactuated position.

The integral studs 40b extend through apertures at the forward ends of the corresponding strips 26 (FIGURES 3 and 6), as mentioned above, so that when one of the tabs 10, 12, 14, 16, 18 or 20 is depressed, its corresponding switch is moved to its actuated position. The movement of the switch strip 26 between its actuated and unactuated position, or vice versa, is achieved by means of the corresponding spring 42. That is, the manual actuation of the tab itself merely moves the toggle mechanism on one side or the other of the dead-center plane, and the corresponding spring 42 then takes over and biases the corresponding member 40, so as to move the switch strip 26 to its actuated or unactuated position, and holds it firmly in one position or the other.

Pads 50 and 52 are provided on the upper surface of the bracket 22, and under the respective ends of the various tabs 10, 12, '14, 16, 18 and 20 to limit the travel of the tabs at their extreme positions.

A pliant member, in the form, for example, of a cord 60 has one of its ends secured to a bracket 62 at one end of the bracket 22, and the cord extends under the bracket and across the front of the bracket, as best shown in FIGURE 4. The other end of the cord 60 is attached to the left side of the bracket 22, as shown in FIGURE 4. The pliant member 60 extends across a plurality of spaced rollers 62.

As shown best in FIGURE 4, the rollers 62 are disposed between the paths of corresponding ones of the strips 26. A plurality of linkage members 64 which may, for example, be in the form of hard-drawn bent wire, extend from respective studs 40b of the members 40 to the pliant member. The linkage members, as shown in FIGURE 4, extend along spaced and parallel paths and are essentially perpendicular to the pliant member. The linking members 64 are hook-shaped at their forward ends, and extend around the pliant member 60. The linkage members 64 form links between the members 40 of the respective toggle mechanisms and the pliant member 60.

Whenever one of the tabs 10, 12, 14, 16, 18 or 20 is depressed, so as to move its corresponding switch strip 26 from its unactuated to its actuated position, the corresponding linkage member '64 moves inwardly with the corresponding toggle mechanism and strip 26. Such movement of the particular linkage member pulls the pliant member 60 in a transverse direction, as shown in FIG- URE 4. Since the pliant member 60 is fastened at each end to the support brackets of the assembly, whenever it is pulled transversely at a particular point between two of the rollers 62, by the linkage member 64 of one of the switch strips 26, it pulls back any previously actuated strip 26 which, likewise, is linked to the pliant member by its linkage member. It will be remembered that the operation of the toggle mechanisms is such, that all the pliant member 60 need do is to pull back the corresponding member 40 beyond its dead-center position by the corresponding linkage member 64, and the corresponding spring 42 will then return the particular switch strip 26 to its unactuated position.

It has been found expedient to sheath the pliant member 60 in a spring 69 which is coextensive with the pliant member, as shown in FIGURES 4 and 5. The purpose of the spring 68 is to provide the pliant member 60 with some resiliency, so that a more positive action of the interlock mechanism is achieved. When the spring 68 is included in the assembly, the length and rigidity requirements of the pliant member 60 is not so critical. The spring 68 provides, therefore, an amount of tolerance to the mechanism. The spring also obviates ambiguities in the mechanism, and assures that only one switch strip 26 will be actuated at any one time.

t'l" he pliant member 60 itself is wrapped around the extreme right hand roller 62, since if the spring 68 were also brought around the end roller, an excessive amount of force would be provided by the spring, so that there would be a tendency for it to return each actuated switch strip 26 to its unactuated position immediately after the, manual pressure had been removed from its actuating tab. By bringing the pliant member itself around the end roller 62, the pliant member, independently of the spring, may be adjusted to exactly the desired degree of tightness for the proper operation of the assembly. The spring 68 also acts as a protection for the pliant member 60, so that the operating life of the assembly is prolonged thereby.

The invention provides, therfore, an improved and excedingly simple interlock apparatus and mechanism. In the practice of the invention, the desired interlock between a series of actuable members is provided essentially by means of an elongated pliant member, and by linking the various actuable members to the pliant member, as described above.

Although a particular embodiment of the invention has been described, it is evident that modifications may be made. The following claims are intended to cover all such modifications which fall within the scope of the invention.

What is claimed is:

1. Apparatus for interlocking a plurality of actuable members so that only one of said members can remain in an actuated position at any given time, said apparatus including:

a supporting means;

an elongated pliant member having its ends afiixed to said supporting means;

an elongated spring coextensive with said pliant member and forming a resilient sheath for said pliant member; and

a plurality of selectively actuable members, each movable between an unactuated position and an actuated position, and each linked to said pliant member so that movement of any one of said actuable members from its unactuated position to its actuated position causes a previously actuated one of said actuable members to return to its unactuated position.

2. Apparatus for interlocking a plurality of actuable members so that only one of said members can remain in an actuated position at any given time, said apparatus including: a supporting bracket; a plurality of selectively actuable members movably mounted on said supporting bracket and spaced from one another along said bracket, each of said members being movable between an actuated and an unactuated position; a plurality of support means mounted on said bracket and spaced from one another along said bracket; an elongated pliant member having each end aflixed to said bracket and extending across said support means; an elongated spring coextensive with said pliant member and forming a resilient sheath for said pliant member; and a plurality of linking members aflixed to respective ones of said actuable members, and each linked to said pliant member between corresponding pairs of said support means, so that movement of any one of said actuable members from its unactuated position to its actuated position causes a previously actuated one of said actuable members to return to its unactuated position.

3. Apparatus for interlocking a plurality of actuable members so that only one of said members can remain in an actuated position at any given time, said apparatus including: a supporting bracket; a plurality of selectively actuable members removably mounted on said supporting bracket and spaced from one another along said bracket, each of said actuable members being movable between an actuated and an unactuated position, and said actuable members being strips slidable on said base along spaced and parallel paths; a plurality of manually operable toggle actuating members mounted on said bracket and coupled to respective ones of said strips; a plurality of support means mounted on said bracket and spaced from one another along said bracket; an elongated pliant member having each end afiixed to said bracket and extending across said support means; and a plurality of linking members allixed to respective ones of said actuable members and each linked to said pliant member between corresponding pairs of said support means, so that movement of any one of said strips from its unactuated position to its actuated position by a toggle movement of its corresponding actuating member causes a previously actuated one of said strips to return to its unactuated position.

4. The apparatus defined in claim 3 and which includes electrical switching contacts mounted on said strips and on said bracket.

5. The apparatus defined in claim 3 and which includes an elongated spring coextensive with said pliant member and forming a resilient sheath for said pliant member.

References Cited UNITED STATES PATENTS 1,458,421 6/1923 Kesling 74-483 XR 2,234,405 3/1941 Hall et al. 74-483 XR HALL C. COE, Primary Examiner.

US. Cl. X.R. 74-501 

